Video processing system and video processing method

ABSTRACT

A video processing system includes: an acquirer that acquires video data including a main video; a format acquirer that acquires a display format that indicates a luminance dynamic range format displayable by a video display apparatus; a generator that generates first characteristics information that indicates first dynamic luminance characteristics that correspond to the display format by using the video data when a luminance dynamic range format of the main video indicated by the video data is different from the display format, the first dynamic luminance characteristics being dynamic luminance characteristics indicating a time-dependent change in luminance characteristics of the main video; and a video transmitter that outputs the first characteristics information generated by the generator.

CROSS-REFERENCE OF RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. § 371 ofInternational Patent Application No. PCT/JP2018/006858, filed on Feb.26, 2018, which in turn claims the benefit of U.S. ProvisionalApplication No. 62/529,727, filed on Jul. 7, 2017, the entiredisclosures of which Applications are incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to a video processing system and a videoprocessing method for processing a video signal.

BACKGROUND ART

Patent Literature (PTL) 1 discloses a display apparatus that updates anHDR signal display method based on dynamic HDR metadata in an HDR (HighDynamic Range) video.

CITATION LIST Patent Literature

-   PTL 1: Japanese Unexamined Patent Application Publication No.    2017-184249

Non-Patent Literature

-   NPL 1: White Paper Blu-ray Disc Read-Only Format (Ultra HD Blu-ray),    Audio Visual Application Format Specifications for BD-ROM Version    3.1, August 2016    (http://www.blu-raydisc.com/Assets/Downloadablefile/BD-ROM_Part3    V3.1_WhitePaper_160729_clean.pdf)

SUMMARY OF THE INVENTION Technical Problem

The present disclosure provides a video processing system or a videoprocessing method that can improve the quality of a video displayed.

Solution to Problem

A video processing system according to an aspect of the presentdisclosure includes: a first acquirer that acquires video data includinga main video; a second acquirer that acquires a display format thatindicates a luminance dynamic range format displayable by a displayapparatus; a generator that generates first characteristics informationthat indicates first dynamic luminance characteristics that correspondto the display format by using the video data when a luminance dynamicrange format of the main video indicated by the video data is differentfrom the display format, the first dynamic luminance characteristicsbeing dynamic luminance characteristics that indicate a time-dependentchange in luminance characteristics of the main video; and an outputterthat outputs the first characteristics information generated by thegenerator.

Advantageous Effect of Invention

The present disclosure can provide a video processing system and a videoprocessing method that can improve the quality of a video displayed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating the evolution of imaging technology.

FIG. 2 is a diagram illustrating the relationship between videoproduction, delivery methods, and display apparatuses when a new videorepresentation is introduced into content.

FIG. 3A is a diagram showing an example of tone mapping.

FIG. 3B is a diagram showing an example of tone mapping.

FIG. 4A is a diagram showing an example of static tone mapping.

FIG. 4B is a diagram showing an example of dynamic tone mapping.

FIG. 5A is a diagram showing examples of EOTFs (Electro-Optical TransferFunctions) for HDR and SDR.

FIG. 5B is a diagram showing examples of inverse EOTFs for HDR and SDR.

FIG. 6 is a diagram showing an example in which graphics are overlaid ona moving image, and the resulting moving image is displayed.

FIG. 7 is a diagram showing the influence of dynamic tone mapping whengraphics are overlaid on a main video.

FIG. 8A is a main flowchart showing an example of an HDR format checkingmethod.

FIG. 8B is a sub-flowchart of the main flowchart shown in FIG. 8Aillustrating an example of a format checking method for checking theformat of a main video.

FIG. 8C is a sub-flowchart of the main flowchart shown in FIG. 8Aillustrating an example of a format checking method for checking theformat of a video display apparatus.

FIG. 9A is a diagram showing a configuration example of dynamic metadatacorresponding to a first option.

FIG. 9B is a diagram showing a configuration example of dynamic metadatacorresponding to a second option.

FIG. 10 is a block diagram showing a configuration of a video processingsystem according to Embodiment 1.

FIG. 11A is a flowchart illustrating the operations of a videoreproduction apparatus according to Embodiment 1.

FIG. 11B is a flowchart illustrating the operations of a video displayapparatus according to Embodiment 1.

FIG. 12 is a diagram showing another configuration example of dynamicmetadata.

FIG. 13 is a block diagram showing a configuration of a video processingsystem according to Embodiment 2.

FIG. 14 is a flowchart illustrating the operations of a videoreproduction apparatus according to Embodiment 2.

FIG. 15 is a block diagram showing a configuration of a video processingsystem according to a first example of Embodiment 3.

FIG. 16 is a flowchart illustrating the operations of a video displayapparatus according to the first example of Embodiment 3.

FIG. 17 is a block diagram showing a configuration of a video processingsystem according to a second example of Embodiment 3.

FIG. 18 is a flowchart illustrating the operations of a video displayapparatus according to the second example of Embodiment 3.

FIG. 19 is a block diagram showing a configuration of a video processingsystem according to Embodiment 4.

FIG. 20 is a block diagram showing a configuration of a tone mappingprocessor.

FIG. 21 is a diagram showing a configuration example of dynamic metadataaccording to Embodiment 4.

FIG. 22A is a diagram showing a variation in the luminance of subtitlesin conventional dynamic tone mapping in the case where graphics aresubtitles.

FIG. 22B is a diagram showing a luminance variation in tone mapping.

FIG. 23 is a diagram showing a luminance variation in tone mapping.

FIG. 24 is a block diagram showing a configuration of video processingsystem 100E according to Embodiment 5.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A video processing system according to an aspect of the presentinvention includes: a first acquirer that acquires video data includinga main video; a second acquirer that acquires a display format thatindicates a luminance dynamic range format displayable by a displayapparatus; a generator that generates first characteristics informationthat indicates first dynamic luminance characteristics that correspondto the display format by using the video data when a luminance dynamicrange format of the main video indicated by the video data is differentfrom the display format, the first dynamic luminance characteristicsbeing dynamic luminance characteristics that indicate a time-dependentchange in luminance characteristics of the main video; and an outputterthat outputs the first characteristics information generated by thegenerator.

Also, the video data may further include second characteristicsinformation that indicates the dynamic luminance characteristics of themain video, and the generator may generate the first characteristicsinformation by converting a luminance dynamic range format of seconddynamic luminance characteristics indicated by the secondcharacteristics information to the display format.

Also, the generator may generate the first characteristics informationby analyzing the main video of the video data to extract the seconddynamic luminance characteristics that indicate the dynamic luminancecharacteristics of the main video, and converting the luminance dynamicrange format of the second dynamic luminance characteristics extractedto the display format.

Also, the video processing system may further include: a tone mappingprocessor that performs a tone mapping process of converting a luminanceof the main video based on conversion characteristics according to thefirst dynamic luminance characteristics indicated by the firstcharacteristics information output from the outputter; and a displaythat displays the main video that has undergone the tone mappingprocess.

Also, the video processing system may further include: a composer thatgenerates a composite video by overlaying graphics on the main video;and an extractor that extracts luminance characteristics of thegraphics. The outputter may further output the composite video and thirdcharacteristics information that indicates the luminance characteristicsof the graphics.

Also, the video processing system may further include: a tone mappingprocessor that performs a tone mapping process of converting a luminanceof the main video based on conversion characteristics according to thefirst dynamic luminance characteristics indicated by the firstcharacteristics information output from the outputter; and a displaythat displays the main video that has undergone the tone mappingprocess. When the composite video is generated by the composer, the tonemapping processor may perform: a first tone mapping process on a firstsection of the main video in which the first dynamic luminancecharacteristics indicated by the first characteristics information aregreater than or equal to the luminance characteristics of the graphicsindicated by the third characteristics information, the first tonemapping process being processing of dynamically changing the luminanceof the main video in the first section based on the conversioncharacteristics according to the first dynamic luminance characteristicsin the first section; and a second tone mapping process on a secondsection of the main video in which the first dynamic luminancecharacteristics are less than the luminance characteristics of thegraphics, the second tone mapping process being processing of changingthe luminance of the main video in the second section based on constantconversion characteristics irrespective of the first dynamic luminancecharacteristics in the second section.

Also, a video processing method according an aspect of the presentinvention is a video processing method in a video processing system, thevideo processing method including: acquiring video data including a mainvideo; acquiring a display format that indicates a luminance dynamicrange format displayable by a display apparatus; generating firstcharacteristics information that indicates first dynamic luminancecharacteristics that correspond to the display format by using the videodata when a luminance dynamic range format of the main video indicatedby the video data is different from the display format, the firstdynamic luminance characteristics being dynamic luminancecharacteristics that indicate a time-dependent change in luminancecharacteristics of the main video; and outputting the firstcharacteristics information generated in the generating of the firstcharacteristics information.

1-1. Background

First, the transition of imaging technology will be described withreference to FIG. 1. FIG. 1 is a diagram illustrating the evolution ofimaging technology.

In order to enhance video image quality, the focus has been given toincrease the number of pixels displayed. Accordingly, standarddefinition (SD) videos (720×480 pixels) and high definition (HD) videos(1920×1080 pixels) are now widely used.

In recent years, in order to achieve even higher image quality,introduction of ultra-high definition (UHD) videos (3840×1920 pixels),or so-called 4K resolution videos (with a 4K resolution of 4096×2048pixels) has started.

Along with the introduction of 4K resolution videos, consideration isalso given to expanding the dynamic range, expanding the color gamut,adding or improving the frame rate, and the like.

Among these, with respect to the dynamic range, HDR (High Dynamic Range)rendering is receiving increased attention as a method for representingbright light, such as specular reflection light, that cannot berepresented by a currently used television signal to be more close toreality while maintaining low light signal gradation. Specifically,conventional television signals are called SDR (Standard Dynamic Range)signals, and the highest luminance is 100 nits. In contrast, in HDRsignals, the highest luminance is expected to be up to 1000 nits ormore. For HDR signals, standardization of mastering display standards iscurrently undertaken by SMPTE (Society of Motion Picture & TelevisionEngineers), ITU-R (International Telecommunications Union Radiocommunications Sector), and the like.

Specific applications of HDR include, as with HD and UHD, broadcasting,packaged media (Blu-ray® disc, and the like), internet delivery, and thelike.

1-2. Relationship Between Generation of Master, Delivery Methods, andDisplay Apparatuses

FIG. 2 is a diagram illustrating the relationship between videoproduction, delivery methods, and display apparatuses when a new videorepresentation is introduced into content.

In the case where a new video representation is introduced (for example,the number of pixels is increased) so as to enhance video image quality,as shown in FIG. 2, it is necessary to (1) change a master for homeentertainment on the video production side. Along with this change, itis also necessary to (2) update the delivery method such asbroadcasting, communication, or a packaged medium, and also (3) updatethe display apparatus such as a television set or a projector fordisplaying the video.

1-3. Tone Mapping

Tone mapping is processing for adjusting, based on the relationshipbetween the luminance of an HDR video and the maximum luminance (DisplayPeak Luminance: DPL) of a video display apparatus, the luminance of thevideo to be less than or equal to DPL by converting the luminance of thevideo if the maximum luminance (Maximum Content Luminance Level: MaxCLL)of the video exceeds DPL. Through this processing, the video can bedisplayed without losing information near the maximum luminance of thevideo. The conversion depends on the characteristics of the videodisplay apparatus, and also depends on how to display the video, andthus different conversion characteristics are used for each videodisplay apparatus.

FIGS. 3A and 3B are diagrams showing examples of tone mapping. FIG. 3Ashows a case where DPL is 500 nits, and FIG. 3B shows a case where DPLis 1000 nits. Also, FIGS. 3A and 3B each show an example of tone mappingperformed when a video having a MaxCLL of 1000 nits is displayed and anexample of tone mapping performed when a video having a MaxCLL of 4000nits is displayed.

As shown in FIG. 3A, in the case where DPL is 500 nits, in both videos,the luminance is converted such that the video can be displayed at up toMaxCLL below 500 nits, but the degree of conversion is higher in thevideo having a higher MaxCLL.

As shown in FIG. 3B, in the case where DPL is 1000 nits, in the videohaving a MaxCLL of 1000 nits, tone mapping is not performed. In thevideo having a MaxCLL of 4000 nits, tone mapping is performed so as toconvert the luminance from 4000 nits to 1000 nits, and the video isdisplayed at that luminance.

1-4. Dynamic Metadata and Dynamic Tone Mapping

FIG. 4A is a diagram showing an example of tone mapping using staticmetadata. FIG. 4B is a diagram showing an example of dynamic tonemapping using dynamic metadata.

As shown in FIG. 4A, in the case where static metadata (MaxCLL) is used,MaxCLL indicates the highest luminance in a video sequence, and thus thevideo display apparatus can only perform tone mapping using a fixedcurve on the video sequence. In contrast, as shown in (a) in FIG. 4B, inthe case where metadata suitable according to the luminance that varieswith time (here, referred to as Dynamic MaxCLL) is used, the videodisplay apparatus does not perform tone mapping when the luminance islow ((b) in FIG. 4B), and performs tone mapping when the luminance ishigh ((c) in FIG. 4B). In this way, optimal tone mapping suitable forthe luminance that varies with time can be implemented. Dynamic metadatadescribes the dynamic luminance characteristics that indicate atime-dependent change in the luminance characteristics of the video. Theluminance characteristics of the video used in the dynamic metadata maybe, for example, the maximum luminance, the average luminance, or thelike of each predetermined section of the video. The present disclosurewill be described by taking the maximum luminance of the video as anexample of the luminance characteristics of the video. As used herein,the term “predetermined section of the video” refers to, for example, ascene, a chapter, a frame, or the like.

1-5. EOTF

Here, EOTF will be described with reference to FIGS. 5A and 5B.

FIG. 5A is a diagram showing examples of EOTFs (Electro-Optical TransferFunctions) for HDR and SDR.

In general, EOTF is what is called a “gamma curve”, which indicates thecorrespondence between code values and luminance values so as to converta code value to a luminance value. That is, EOTF is relationshipinformation that indicates the correspondence relationship between aplurality of code values and luminance values.

Also, FIG. 5B is a diagram showing examples of inverse EOTFs for HDR andSDR.

Inverse EOTF indicates the correspondence between the luminance valueand the code value, and is used to convert the luminance value to thecode value by quantizing the luminance value inversely to EOTF. That is,inverse EOTF is relationship information that indicates thecorrespondence relationship between luminance values and a plurality ofcode values. For example, in the case where the luminance values of anHDR-compatible video are represented by code values on a 10 bit grayscale, luminance values in an HDR luminance range of up to 10000 nitsare quantized and mapped to 1024 integer values ranging from 0 to 1023.That is, by performing quantization based on the inverse EOTF, aluminance value in a luminance range of 0 to 10000 nits (the luminancevalues of the HDR-compatible video) is converted to an HDR signal with10-bit code value. With HDR-compatible EOTF (hereinafter referred to as“HDR EOTF”) or HDR-compatible inverse EOTF (hereinafter referred to as“HDR inverse-EOTF”), it is possible to represent higher luminance valueshigher than those of SDR-compatible EOTF (hereinafter referred to as“SDR EOTF”) or SDR-compatible inverse EOTF (hereinafter referred to asSDR inverse-EOTF). For example, in FIGS. 5A and 5B, the maximumluminance value (peak luminance) is 10000 nits. That is, the HDRluminance range includes the entire SDR luminance range, and the HDRpeak luminance is higher than the SDR peak luminance. The HDR luminancerange is a luminance range in which the maximum value is increased from100 nits, which is the maximum value of the SDR luminance range, to10000 nits.

For example, an example of the HDR EOTF and the HDR inverse-EOTFincludes SMPTE 2084 standardized by the Society of Motion Picture andTelevision Engineers (SMPTE) founded in the United States.

1-6. Overlaying Graphics on Video

FIG. 6 is a diagram showing an example in which graphics such as a menuand subtitles are overlaid on a moving image, and the moving image isdisplayed on a video display apparatus. Here, an example of Ultra HDBlu-ray is shown.

A set of moving images before graphics are overlaid will be referred toas a main video. With Ultra HD Blu-ray, graphics are prepared in HDresolution. A video reproduction apparatus performs HD-UHD conversion onthe graphics in HD resolution so as to generate graphics in UHDresolution. Then, the video reproduction apparatus overlays the obtainedgraphics in UHD resolution with the main video having UHD resolution.Then, the video reproduction apparatus transmits the video resultingfrom the overlay process to a video display apparatus via HDMI®(High-Definition Multimedia Interface). The video display apparatusdisplays the transmitted video in HDR.

Also, the video reproduction apparatus determines dynamic metadata basedon the variation of the luminance of the main video with time, andtransmits the dynamic metadata to the video display apparatus via HDMI.The video display apparatus performs dynamic tone mapping on a videosignal of the video obtained by overlaying subtitles and menus on themain video based on the transmitted dynamic metadata.

The same applies to an HDR video that is displayed through an OTT (overthe top) service via broadcasting or communication and in which a menuor subtitles are overlaid on a main video, and the resulting video isdisplayed on a video display apparatus.

1-7. Problem Arising when Performing Dynamic Tone Mapping on Video Datawhere Graphics are Overlaid on Moving Image

In the dynamic metadata method, metadata regarding the luminance of theHDR video such as luminance distribution is designated for each frame,and the metadata is transmitted to the video display apparatus togetherwith the video signal. The video display apparatus performs processingsuch as luminance conversion based on the transmitted metadata accordingto the display capabilities of the video display apparatus such asmaximum luminance. The dynamic metadata method as described above isreceiving increased attention as a method for displaying a video at aconstant quality as much as possible irrespective of the displayperformance of a video display apparatus such as luminance.

However, dynamic metadata varies with time, and thus there is a problemin that a video that needs to be displayed stably is not displayedstably.

If the video to be displayed is a video or a set of so-called movingimages that is simultaneously edited or supervised, processing can beperformed considering the state of the video to some degree. Whengraphics data such as subtitles or a menu whose luminance is essentiallyconstant and does not vary at all is overlaid on a main video composedof a set of moving images as described above and displayed, due to theprocessing that uses dynamic metadata, a negative effect occurs such asvariation of the luminance or color of the graphics that essentiallyneeds to be constant. This negative effect becomes more prominent as theluminance of the main video is higher and the luminance of the videodisplay apparatus is lower.

FIG. 7 is a diagram showing the influence of dynamic tone mapping whengraphics are overlaid on a main video. It is assumed here that, as shownin (a) in FIG. 7, graphics to be overlaid has a luminance of 350 nits.As shown in (b) in FIG. 7, in a section of the main video that has a lowluminance, tone mapping is not performed, and thus the graphics aredisplayed on a video display apparatus at a luminance of 350 nits thatis the original luminance of the graphics. On the other hand, as shownin (c) in FIG. 7, in a section of the main video that has a highluminance, tone mapping is performed, and thus the graphics aredisplayed on the video display apparatus at a luminance lower than 350nits. In this way, the graphics luminance that essentially needs to beconstant varies with time, resulting in an undesired state. In thisexample, only the influence on the luminance is considered, but in anactual video display apparatus, the influence may also be exerted oncolor components, and thus colors may also be affected.

1-8. Example of HDR Format Checking Method

At present, some HDR formats in which dynamic tone mapping can beperformed are currently proposed and standardized. An HDR format is anexample of a luminance dynamic range format. Accordingly, the videoreproduction apparatus needs to check which HDR format each of the mainvideo, the video reproduction apparatus, and the video display apparatussupports, reproduce the main video supported by the video displayapparatus and output the reproduced main video to the video displayapparatus.

FIGS. 8A to 8C are flowcharts illustrating an example of an HDR formatchecking method. FIG. 8A is a main flowchart illustrating an example ofan HDR format checking method. FIG. 8B is a sub-flowchart of the mainflowchart shown in FIG. 8A illustrating an example of a format checkingmethod for checking the format supported by the main video. FIG. 8C is asub-flowchart of the main flowchart shown in FIG. 8A illustrating anexample of a format checking method for checking the format supported bythe video display apparatus.

In an Ultra HD Blu-ray disc, Mandatory HDR and a plurality of OptionHDRs are specified as HDR formats. Accordingly, in an Ultra HD Blu-raydisc, a main video that supports only Mandatory HDR, or a main videothat supports Mandatory HDR and Option HDR is recorded. In the casewhere Option HDR is recorded, at least one of the plurality of OptionHDRs is recorded. Option HDR videos are higher quality videos thanMandatory HDR videos.

As shown in FIG. 8A, the video reproduction apparatus first checks theluminance dynamic range format of the main video (S1).

Specifically, as shown in FIG. 8B, the video reproduction apparatuschecks the flags of the HDR formats listed on a reproduction controllist of the main video (S11). In this way, the video reproductionapparatus checks the flags of the HDR formats and determines the HDRformat supported by the main video.

Next, the video reproduction apparatus checks the HDR format(hereinafter referred to as “display format”) supported by the videodisplay apparatus (S2). That is, the video reproduction apparatus checksthe display format that is the luminance dynamic range formatdisplayable by the video display apparatus.

Specifically, as shown in FIG. 8C, the video reproduction apparatusissues a request to transmit EDID of the video display apparatus to thevideo display apparatus via HDMI (S21).

Next, the video reproduction apparatus acquires EDID of the videodisplay apparatus from the video display apparatus via HDMI (S22).

Then, the video reproduction apparatus checks the acquired EDID for thedisplay format of the video display apparatus (S23).

In this way, by performing steps S1 and S2, the video reproductionapparatus checks, before it reproduces the main video, the HDR formatsupported by the main video and the HDR format supported by the videodisplay apparatus to which the video reproduction apparatus isconnected. That is, here, the video reproduction apparatus checks theOption HDR.

After that, referring back to FIG. 8A, the video reproduction apparatusdetermines whether or not the HDR format supported by the videoreproduction apparatus includes the Option HDR of the main video (S3).

If it is determined that the HDR format supported by the videoreproduction apparatus includes the Option HDR of the main video (Yes inS3), the video reproduction apparatus determines whether or not thedisplay format of the video display apparatus includes the Option HDR ofthe main video (S4). In this case, in step S4, a determination is madewith respect to the HDR format supported by the video reproductionapparatus and the Option HDR included in the main video in step S3.

If it is determined that the display format of the video displayapparatus includes the Option HDR of the main video (Yes in S4), thevideo reproduction apparatus reproduces the main video in the Option HDR(S5). That is, if all of the main video, the video reproductionapparatus, and the video display apparatus support the same Option HDR,the video reproduction apparatus reproduces the main video in thatOption HDR.

If, on the other hand, it is determined that the HDR format supported bythe video reproduction apparatus does not include the Option HDR of themain video (No in S3), or if it is determined that the display format ofthe video display apparatus does not include the Option HDR of the mainvideo (No in S4), the video reproduction apparatus reproduces the mainvideo in Mandatory HDR. That is, if any one of the main video, the videoreproduction apparatus, and the video display apparatus does not supportthe Option HDR, the video reproduction apparatus reproduces in MandatoryHDR. It is assumed that HDR-compatible devices support Mandatory HDR.

1-9. Problems Arising when Performing Dynamic Tone Mapping in Pluralityof HDR Formats Problem 1

As described above, in the case where a video reproduction apparatus anda video display apparatus, which do not support Option HDRs, areconnected to each other, the main video is reproduced and displayed inMandatory HDR, and thus there is a problem in that it is not possible toperform dynamic tone mapping. Also, in each Option HDR, some parametersare defined. If there are further options in the parameters, a situationmay arise in which a first option is recorded in the main video data,but the video display apparatus does not support the first option, butsupports a second option that is different from the first option.However, in such a situation, despite the fact that the main video, thevideo reproduction apparatus, and the video display apparatus support anOption HDR format, it is not possible to display the video in the OptionHDR format depending on the options of the parameters of the Option HDR.Accordingly, in such a video processing system, the main video isreproduced and displayed in Mandatory HDR, and it is therefore notpossible to perform dynamic tone mapping. Alternatively, processing isperformed only on the mandatory portion of the Option HDR, and thusdynamic tone mapping poorer than desired is performed, and the video isdisplayed with poor quality.

FIGS. 9A and 9B show examples of different options in an Option HDR.FIG. 9A is a diagram showing a configuration example of dynamic metadatacorresponding to a first option. FIG. 9B is a diagram showing aconfiguration example of dynamic metadata corresponding to a secondoption. In FIGS. 9A and 9B, illustration of the elements that are notrelevant to the present disclosure is omitted.

As shown in the diagrams, in the first option, for example, the averagedata value and the value of data value distribution information of thebasic tone mapping information are defined by data values. On the otherhand, in the second option, they are defined by luminance values. Also,although not shown here, there may be cases where values are expressedin the same unit and have the same definition but the number of valuesis different. Also, data values or luminance values such as the averagedata value and the value of data value distribution information of thebasic tone mapping information may be expressed in values converted innit, which is a unit of brightness.

Problem 2

In the case of metadata based on data values such as an example ofdynamic metadata corresponding to the first option shown in FIG. 9A, itis difficult to perform processing based on the luminance of graphicsoverlaid on the main video. Specifically, in the case where, dependingon the graphics luminance, dynamic tone mapping is not performed whenthe luminance is lower than or equal to the graphics luminance, becausethe metadata corresponding to the first option is based on data values,or in other words, RGB values, rather than luminance information, themeans that performs dynamic tone mapping needs to perform processingsuch that the graphics luminance information of the graphics and theluminance information of the metadata are expressed in the same unit. Inthe case of a Blu-ray disc, in particular, the graphics data on the discinclude luminance information and color information, rather than RGBvalues, and it is therefore more difficult to perform the processing.

Problem 3

Problem 1 is the problem caused when one Option HDR format includes aplurality of options, but even if the reproduction apparatus supports aplurality of HDR formats in which dynamic tone mapping can be performed,if the video display apparatus does not support a first HDR formatsupported by the main video to be reproduced, (i) it is not possible todisplay the video in the first HDR format. Alternatively, if the firstHDR format supported by the main video to be reproduced is Option HDR,and the main video includes Mandatory HDR, (ii) the main video isdisplayed only in the Mandatory HDR format. Accordingly, in such a videoprocessing system, there is a problem in that it is not possible toimplement dynamic tone mapping that is a feature of the Option HDR.

1-10. Solution

In the present disclosure, the following solutions are used.

A first method, which is a method for solving Problem 1, will bedescribed. In the first method, in the case where a video displayapparatus connected to a video reproduction apparatus via a video signaltransmitting means such as an HDMI cable does not support a first optionof a predetermined HDR format, but supports a second option of thepredetermined HDR format, the video reproduction apparatus generates asecond option portion from a first option portion of the dynamicmetadata acquired from the main video to be reproduced by the videoreproduction apparatus. Then, the video reproduction apparatus (i)replaces the first option portion of the acquired dynamic metadata withthe generated second option portion; or (ii) adds the generated secondoption portion to the acquired dynamic metadata. After that, the videoreproduction apparatus transmits the dynamic metadata including thesecond option portion to the video display apparatus via the videosignal transmitting means. The video display apparatus acquires thedynamic metadata including the second option portion, and executesdynamic tone mapping according to the second option of the predeterminedHDR format by using the second option portion of the acquired dynamicmetadata.

Next, a second method, which is a method for solving Problem 1, will bedescribed. In the second method, in the case where a video displayapparatus connected to a video reproduction apparatus via a video signaltransmitting means such as an HDMI cable does not support a first optionof a predetermined HDR format, but supports a second option of thepredetermined HDR format, the video reproduction apparatus generates asecond option portion of dynamic metadata from the main video to bereproduced by the video reproduction apparatus. Then, the videoreproduction apparatus (i) replaces a first option portion of thedynamic metadata of the main video with the generated second optionportion; or (ii) adds the generated second option portion to theacquired dynamic metadata. After that, the video reproduction apparatustransmits the dynamic metadata including the second option portion tothe video display apparatus via the video signal transmitting means. Thevideo display apparatus acquires the dynamic metadata including thesecond option portion, and executes dynamic tone mapping according tothe second option of the predetermined HDR format by using the secondportion of the acquired dynamic metadata.

Next, a third method, which is a method for solving Problem 1, will bedescribed. In the third method, the function of generating the secondoption portion from the first option portion, which was explained in thefirst method, or the function of generating the second option portionfrom the main video, which was explained in the second method, isprovided to the video display apparatus. That is, in the case where avideo display apparatus connected to a video reproduction apparatus viaa video signal transmitting means such as an HDMI cable does not havethe display processing function of displaying a main video correspondingto a first option of a predetermined HDR format, but has the processingfunction of processing a main video corresponding to a second option ofthe predetermined HDR format, the video reproduction apparatusreproduces the main video corresponding to the first option, and outputsa reproduction signal of the main video. The video display (i) generatesa second option portion from a first option portion of dynamic metadatatransmitted together with the main video, (ii) generates a second optionportion from the main video, or generating a second option portion byusing both methods (i) and (ii). Then, the video display apparatusexecutes dynamic tone mapping by using the generated second optionportion.

Next, a fourth method, which is a method for solving Problem 2, will bedescribed. In the fourth method, in addition to the first method or thesecond method, the video reproduction apparatus performs inclusion ofgraphics luminance information at the time of generating the secondoption portion of the dynamic metadata. That is, the video reproductionapparatus adds, to the second option portion, graphics luminanceinformation of the graphics to be overlaid on the main video. The videodisplay apparatus acquires the dynamic metadata including the secondoption portion, and performs, on a section in which the luminance of themain video corresponding to the second option is greater than or equalto the graphics luminance, a first tone mapping process of dynamicallychanging conversion characteristics according to the second optionportion of that section by using the acquired dynamic metadata, andperforms a second tone mapping process that uses constant conversioncharacteristics on a section in which the luminance of the main videocorresponding to the second option is less (darker) than the graphicsluminance.

Next, a fifth method, which is a method for solving Problem 3, will bedescribed. In the fifth method, a case will be considered in which thevideo reproduction apparatus supports a plurality of HDR formats inwhich dynamic tone mapping can be performed. In the case where the mainvideo supports a first HDR format that is one of a plurality of HDRformats, and the video display apparatus connected to the videoreproduction apparatus supports a second HDR format that is another oneof the plurality of HDR formats, at the time of reproducing the mainvideo, the video reproduction apparatus dynamically generates, from themain video that is being reproduced, dynamic metadata that is needed inthe second HDR format supported by the video display apparatus, andtransmits the generated dynamic metadata to the video display apparatus.As a result, the video display apparatus acquires the main video and thedynamic metadata corresponding to the second HDR format, and displaysthe acquired main video in the second HDR format by using the acquireddynamic metadata.

With the method described above, with respect to an HDR video signaltransmitted via broadcasting, a packaged medium such as a Blu-ray disc,or internet delivery such as OTT, in the case where there are aplurality of options in an HDR format in which dynamic tone mapping canbe performed and that is supported by the HDR video signal, and the HDRvideo signal supports the first option, and the video display apparatusdoes not support the first option, but supports the second option, thevideo reproduction apparatus generates a second option portion from thefirst option portion of the dynamic metadata or the HDR video signal,and transmits the dynamic metadata including the second option portionto the video display apparatus. Accordingly, the video display apparatuscan implement dynamic tone mapping provided by the HDR format by usingthe second option portion supported by the video display apparatus.

Also, when performing dynamic tone mapping, the video display apparatuscan, by using the second option, reduce the influence of the dynamictone mapping on graphics such as a menu and subtitles, with which it isdifficult to cope by using the first option, and thus can displaysubtitles and a menu in a stable manner.

Also, in the case where there are a plurality of HDR formats in whichdynamic tone mapping can be performed, and the HDR video signal supportsa first HDR format, and the video display apparatus supports a secondHDR format, the video reproduction apparatus generates dynamic metadatain the second HDR format from the first HDR format or the HDR videosignal. Accordingly, the video display apparatus can implement dynamictone mapping in the second HDR format.

2. Embodiment 1

In the present embodiment, in the case where a video display apparatusconnected to a video reproduction apparatus via a video signaltransmitting means such as an HDMI cable does not support a first optionof a predetermined HDR format, but supports a second option of thepredetermined HDR format, the video reproduction apparatus generates asecond option portion from a first option portion of dynamic metadataacquired from a main video to be reproduced, and (i) replaces the firstoption portion of the acquired dynamic metadata with the generatedsecond option portion; or (ii) adds the second option portion to theacquired dynamic metadata. After that, the video reproduction apparatustransmits the dynamic metadata including the second option portion tothe video display apparatus via the video signal transmitting means. Thevideo display apparatus acquires the dynamic metadata including thesecond option portion, and executes dynamic tone mapping according tothe second option of the predetermined HDR format by using the secondportion of the acquired dynamic metadata.

[2-1. Configuration of Video Processing System]

FIG. 10 is a block diagram showing a configuration of video processingsystem 100 according to Embodiment 1. Video processing system 100 shownin FIG. 10 includes video reproduction apparatus 101 and video displayapparatus 102.

Video reproduction apparatus 101 reproduces a video, and outputs theobtained video to video display apparatus 102. Video reproductionapparatus 101 includes acquirer 111, demultiplexer 112, main videodecoder 113, subtitles decoder 114, menu decoder 115, metadata acquirer116, format acquirer 117, generator 118, graphics composer 119, mainvideo composer 120, and video transmitter 121.

Acquirer 111 acquires a video signal. For example, in the case wherevideo reproduction apparatus 101 is a disc reproduction apparatus,acquirer 111 acquires a video signal by reproducing a disc. In the casewhere video reproduction apparatus 101 is a broadcast receptionapparatus, acquirer 111 acquires a video signal by receiving a broadcastwave. In the case where video reproduction apparatus 101 is an internetbroadcast reception apparatus, acquirer 111 acquires a video signal byreceiving an internet broadcast.

Demultiplexer 112 outputs a main video signal, a subtitles signal, and amenu signal that have been encoded and included in the video signal tomain video decoder 113, subtitles decoder 114, and menu decoder 115,respectively.

Main video decoder 113 decodes the encoded main video signal output fromdemultiplexer 112.

Subtitles decoder 114 decodes the encoded subtitles signal output fromdemultiplexer 112. Also, subtitles decoder 114 determines whether or notto display subtitles based on a user's operation or the like, andselects the type of subtitles to be displayed. Subtitles decoder 114outputs the selected subtitles to graphics composer 117 when displayingthe subtitles.

Menu decoder 115 decodes the encoded menu signal output fromdemultiplexer 112. Also, menu decoder 115 determines whether or not todisplay a menu based on a user's operation or the like, and selects thetype of menu to be displayed. Menu decoder 115 outputs the selected menuto graphics composer 117 when displaying the menu. Menu decoder 115 mayoverlay and display a menu by using, not only information from the videosignal, but also a program that runs on video reproduction apparatus101.

Metadata acquirer 116 acquires main video dynamic metadata. For example,metadata acquirer 116 generates main video dynamic data based oninformation included in the main video signal. The description will begiven assuming that main video dynamic metadata corresponding to thefirst option is acquired by metadata acquirer 116.

Format acquirer 117 acquires, from video display apparatus 102, adisplay format indicating a luminance dynamic range format displayableby video display apparatus 102. Here, the option of the HDR formatsupported by the display format of video display apparatus 102 is asecond option, and thus format acquirer 117 acquires a display formatindicating the second option.

The format (first option) supported by the main video dynamic metadataacquired by metadata acquirer 116 and the display format (second option)acquired by format acquirer 117 are different, and thus generator 118generates a second option portion from the first option portion of themain video dynamic metadata. Then, generator 118 replaces the firstoption portion of the main video dynamic metadata with the generatedsecond option portion, or adds the generated second option portion tothe main video dynamic metadata. In this way, in the case where theluminance dynamic range format of the video indicated by the video datais different from the display format of the video display apparatus,generator 118 converts the format of the main video dynamic metadata tothe display format.

Graphics composer 119 generates graphics information by composingsubtitles and menus. As described above, graphics composer 119 mayconvert the resolution of subtitles and menus. For example, in the caseof Ultra HD Blu-ray, graphics composer 119 may convert subtitles andmenus in HD resolution to subtitles and menus in UHD resolution.

Also, graphics composer 119 generates graphics information. In the casewhere the generated graphics information is overlaid on the main video,graphics composer 119 sets graphics luminance information as a valueother than “0” or a “value indicating that there are graphics”, andtransmits the graphics luminance information to video transmitter 121.In the case where the generated graphics information is not overlaid onthe main video, graphics composer 119 sets graphics luminanceinformation as “0” or a “value indicating that there are no graphics”,and transmits the graphics luminance information to video transmitter121. The graphics luminance information may be generated by a programinstalled on video reproduction apparatus 101, or by any other means.

Main video composer 120 generates a video signal by overlaying thegraphics information generated by graphics composer 119 on the mainvideo obtained by main video decoder 113.

Video transmitter 121 transmits the video signal generated by main videocomposer 120 and dynamic metadata to video display apparatus 102 via thevideo signal transmitting means such as an HDMI cable. The dynamicmetadata includes the main video dynamic metadata acquired by metadataacquirer 116 and the graphics luminance information generated bygraphics composer 119. That is, video transmitter 121 outputs the mainvideo dynamic metadata including the second option portion generated bygenerator 118 to video display apparatus 102.

Next, a configuration of video display apparatus 102 will be described.Video display apparatus 102 includes video receiver 131, metadataacquirer 132, tone mapping processor 133, display 134, and notifier 135.

Video receiver 131 receives the video signal and the dynamic metadatatransmitted from video reproduction apparatus 101. Video receiver 131separates the video signal from the dynamic metadata, and transmits thevideo signal to tone mapping processor 133 and the dynamic metadata tometadata acquirer 132. Metadata acquirer 132 transmits the main videodynamic metadata included in the dynamic metadata and the graphicsluminance information to tone mapping processor 133 as a control signal.

Tone mapping processor 133 performs a tone mapping process on the videosignal in accordance with the main video dynamic metadata. Tone mappingprocessor 133 performs a tone mapping process of converting theluminance of the main video by using conversion characteristicsaccording to the second option portion of the dynamic metadata supportedby the output display format. Specifically, when the graphics luminanceinformation indicates “0” or a “value indicating that there are nographics”, tone mapping processor 133 performs a tone mapping process(dynamic tone mapping process) on the video signal in accordance withthe main video dynamic metadata. On the other hand, when the graphicsluminance information indicates a value other than “0” or a “valueindicating that there are graphics”, tone mapping processor 133 performsa tone mapping process so as to reduce the influence of dynamic tonemapping on the overlaid graphics. Display 134 displays the video signalthat has undergone the tone mapping process.

Notifier 135 transmits EDID including the display format of videodisplay apparatus 102 to video reproduction apparatus 101. For example,upon receiving a request to transmit EDID from video reproductionapparatus 101, notifier 135 transmits EDID to video reproductionapparatus 101 via the video signal transmitting means such as an HDMIcable.

[2-2. Operations of Video Processing System]

In the case where the first option portion and the second option portionof the dynamic metadata are configured as shown in FIGS. 9A and 9B,metadata acquirer 116 acquires the main video dynamic metadata includingthe first option portion and the mandatory portion of Option HDR basedon the information included in the main video.

A flow of operations of video processing system 100 performed in thiscase will be described. FIG. 11A is a flowchart illustrating theoperations of video reproduction apparatus 101 according to Embodiment1.

After the reproduction of a video starts, in video reproductionapparatus 101, metadata acquirer 116 extracts, for each frame of themain video, the mandatory portion and the first option portion of thedynamic metadata from the main video (S31).

Then, generator 118 generates a second option portion from the firstoption portion of the dynamic metadata extracted by metadata acquirer116 (S32).

Next, generator 118 replaces the first option portion of the main videodynamic metadata with the generated second option portion, or adds thegenerated second option portion to the main video dynamic metadata(S33). After that, generator 118 transmits the main video dynamicmetadata including the mandatory portion and the second option portionto video transmitter 121. Then, video transmitter 121 transmits the mainvideo dynamic metadata together with the main video to video displayapparatus 102 via the video signal transmitting means.

Then, video reproduction apparatus 101 determines whether thereproduction of the video is completed or an operation to stop thereproduction of the video is performed (S34). If it is determined thatthe reproduction of the video is completed or an operation to stop thereproduction of the video is performed, video reproduction apparatus 101ends the reproduction of the video. That is, video reproductionapparatus 101 repeats the processing operations of steps S31 to S34until the reproduction of the video is completed or an operation to stopthe reproduction of the video is performed. For example, the processingoperations are repeatedly performed for each frame or every plurality offrames.

FIG. 11B is a flowchart illustrating the operations of video displayapparatus 102 according to Embodiment 1.

In video display apparatus 102, video receiver 131 receives the videosignal and the dynamic metadata (S41). Video receiver 131 transmits thereceived video signal as the main video to tone mapping processor 133and the dynamic metadata to metadata acquirer 132.

Metadata acquirer 132 acquires the main video dynamic metadata includingthe second option portion (S42).

Then, tone mapping processor 133 starts a tone mapping process accordingto the second option portion at the same time when the display of thevideo starts (S43).

After that, display 134 displays the video that has undergone the tonemapping process of tone mapping processor 133 (S44).

Then, video display apparatus 102 determines whether or not thereception of the video is completed or an operation to turn off thedisplay is performed (S45). If it is determined that the reception ofthe video is completed or an operation to turn off the display isperformed, video display apparatus 102 ends the display of the video.That is, video display apparatus 102 repeats the processing operationsin steps S41 to S45 until the reception of the video is completed or anoperation to turn off the display is performed. For example, theprocessing operations are repeatedly performed for each frame or everyplurality of frames.

FIG. 12 is a diagram showing another configuration example of dynamicmetadata. In FIG. 12, illustration of the elements that are not relevantto the present disclosure is omitted.

The configuration example of dynamic metadata shown in FIG. 12 isdifferent from those of FIGS. 9A and 9B in that the mandatory portion,the first option portion, and the second option portion are specified bythe item record position. In the case of the configuration example shownin FIG. 12, in the metadata as the first option portion, the secondoption portion has a value of “0” or a “value indicating invalidity”. Inthe metadata as the second option portion, the first option portion hasa value of “0” or a “value indicating invalidity”. The first optionportion and the second option portion may both have effective values.

Also, the generation of the second option portion from the first optionportion of the dynamic metadata can be performed by, for example,converting the value of the first option to a value corresponding to thesecond option by using the data value distribution and the average datavalue based on the video specifications of the main video (the use ofthe main video corresponding to the first option and the use of the mainvideo corresponding to the second option). In the case where RGB valuesare designated as data values in the first option portion, the firstoption portion can be completely converted to the second option portion.In both the dynamic metadata configuration shown in FIGS. 9A and 9B andthe dynamic metadata configuration shown in FIG. 12, the number ofdistribution information elements of the first option and the number ofdistribution information elements of the second option may not match.Even in such a case, if at least distribution information that isnecessary to generate the second option portion is included in the firstoption portion, the first option portion can be converted directly tothe second option portion. On the other hand, if distributioninformation that is necessary to generate the second option portion isnot included in the first option portion, by using distributioninformation obtained by supplementing necessary distribution informationfrom the distribution information of the first option, the first optionportion can be converted to the second option portion.

3. Embodiment 2

Embodiment 2 will be described. Embodiment 1 is configured such that thesecond option portion corresponding to the display format of the videodisplay apparatus is generated from the first option portion of thedynamic metadata of the main video, but the configuration is not limitedthereto. In Embodiment 2, an example will be described in which thesecond option portion is generated from the main video. That is, in thepresent embodiment, in the case where a video display apparatusconnected to a video reproduction apparatus via a video signaltransmitting means such as an HDMI cable does not support a first optionof a predetermined HDR format, but supports a second option of thepredetermined HDR format, the video reproduction apparatus generates asecond option portion of dynamic metadata from the main video to bereproduced by the video reproduction apparatus. Then, the videoreproduction apparatus (i) replaces the first option portion of thedynamic metadata of the main video with the generated second optionportion; or (ii) adds the generated second option portion to theacquired dynamic metadata. After that, the video reproduction apparatustransmits the dynamic metadata including the second option portion tothe video display apparatus via the video signal transmitting means. Thevideo display apparatus acquires the dynamic metadata including thesecond option portion, and executes dynamic tone mapping according tothe second option of the predetermined HDR format by using the secondportion of the acquired dynamic metadata.

[3-1. Configuration of Video Processing System]

FIG. 13 is a block diagram showing a configuration of video processingsystem 100A according to Embodiment 2. Video reproduction apparatus 101Aaccording to the present embodiment is different from video reproductionapparatus 101 according to Embodiment 1 in that the function ofgenerator 118A is different. Other structural elements of videoreproduction apparatus 101A are the same as those of video reproductionapparatus 101 according to Embodiment 1, and thus a detailed descriptionthereof will be omitted.

The format (first option) supported by the main video dynamic metadataacquired by metadata acquirer 116 and the display format (second option)acquired by format acquirer 117 are different, and thus generator 118Agenerates a second option portion of dynamic metadata from the mainvideo output from main video decoder 113. Then, generator 118A replacesthe first option portion of the main video dynamic metadata with thegenerated second option portion, or adds the generated second optionportion to the main video dynamic metadata. In this way, generator 118Aextracts the dynamic metadata of the main data by analyzing the mainvideo, and converts the luminance dynamic range format of the extracteddynamic metadata to the display format.

[3-2. Operations of Video Processing System]

In the case where the first option portion and the second option portionof the dynamic metadata are configured as shown in FIGS. 9A and 9B,metadata acquirer 116 acquires the main video dynamic metadata includingthe first option portion and the mandatory portion of Option HDR.

A flow of operations of video processing system 100A performed in thiscase will be described. FIG. 14 is a flowchart illustrating theoperations of video reproduction apparatus 101A according to Embodiment2. The operations of video reproduction apparatus 101A according toEmbodiment 2 are different from the operations of video reproductionapparatus 101 according to Embodiment 1 in that step S32A is performedinstead of step S32. Accordingly, only step S32A will be described, anda description of other steps will be omitted.

In video processing system 100A, after step S31, generator 118A analyzesthe luminance characteristics of the main video output from main videodecoder 113, and generates dynamic metadata corresponding to the secondoption (or in other words, a second option portion) from the result ofthe analysis (S32A).

After that, video reproduction apparatus 101A performs the sameprocessing operations as those of step S33 and the subsequent stepsshown in FIG. 11A.

As in the case of another configuration example of dynamic metadatashown in FIG. 12, in the metadata as the first option portion, thesecond option portion has a value of “0” or a “value indicatinginvalidity”. In the metadata as the second option portion, the firstoption portion has a value of “0” or a “value indicating invalidity”.The first option portion and the second option portion may both haveeffective values.

Also, the generation of the second option portion of dynamic metadatafrom the main video can be performed by, for example, for each frame ofthe main video, acquiring the luminance values of all pixel data of themain video, obtaining the distribution thereof through statisticalprocessing, and performing calculation according to the specification ofthe second option.

In the data of the main video, in the case where the values of thesecond option are defined as code values indicating the luminance valuesof displayed luminance, the second option portion of dynamic metadatamay be determined in the manner described below. In this case, the dataof the main video includes code values associated with predeterminedluminance values in input/output characteristics (EOTF: Electro-OpticalTransfer Function) specified by the HDR format when display processingis performed in accordance with EOTF. Accordingly, first, the processingin accordance with EOTF is performed so as to convert the code values ofthe main video to luminance values, and statistical processing isperformed using the luminance values obtained by the conversion. Then,calculation is performed in accordance with the specification of thesecond option by using the result of the statistical processing so as toobtain a second option portion of dynamic metadata.

4. Embodiment 3

Embodiment 3 will be described. Embodiments 1 and 2 are configured suchthat the second option portion corresponding to the display format ofthe video display apparatus is generated by the video reproductionapparatus, but in Embodiment 3, an example will be described in whichthe second option portion is generated by the video display apparatus.That is, in the present embodiment, in the case where a video displayapparatus connected to a video reproduction apparatus via a video signaltransmitting means such as an HDMI cable does not have the displayprocessing function of displaying a main video corresponding to a firstoption of a predetermined HDR format, but has the processing function ofprocessing a main video corresponding to a second option of thepredetermined HDR format, the video reproduction apparatus reproducesthe main video corresponding to the first option, and outputs areproduction signal of the main video. The video display apparatus (i)generates a second option portion from the first option portion of thedynamic metadata transmitted together with the main video, (ii)generates a second option portion from the main video, or generates asecond option portion by using the two methods (i) and (ii). Then, thevideo display apparatus executes dynamic tone mapping using thegenerated second option portion.

[4-1. Configuration of Video Processing System of First Example]

FIG. 15 is a block diagram showing a configuration of video processingsystem 100B according to a first example of Embodiment 3.

Video reproduction apparatus 101B according to the first example of thepresent embodiment is different from video reproduction apparatus 101according to Embodiment 1 in that video reproduction apparatus 101B doesnot include format acquirer 117 and generator 118. Accordingly, videotransmitter 121 transmits the video signal generated by main videocomposer 120 and the dynamic metadata including the first option portionto video display apparatus 102B via a video signal transmitting meanssuch as an HDMI cable. Other structural elements of video reproductionapparatus 101B are the same as those of video reproduction apparatus 101according to Embodiment 1, and thus a detailed description thereof isomitted here.

Also, video display apparatus 102B according to the first example of thepresent embodiment is different from video display apparatus 102according to Embodiment 1 in that video display apparatus 102B furtherincludes generator 136 but does not include notifier 135. Otherstructural elements of video display apparatus 102B are the same asthose of video display apparatus 102 according to Embodiment 1, and thusa detailed description thereof is omitted here.

The format (first option) supported by the main video dynamic metadataacquired by metadata acquirer 132 and the display format (second option)are different, and thus generator 136 generates a second option portionfrom the first option portion of the main video dynamic metadata. Then,generator 136 replaces the first option portion of the main videodynamic metadata with the generated second option portion. In this way,in the case where the luminance dynamic range format of the videoindicated by the video data is different from the display format of thevideo display apparatus, generator 136 converts the format of the mainvideo dynamic metadata to the display format.

[4-2. Operations of Video Processing System of First Example]

First, video reproduction apparatus 101B transmits the main videodynamic metadata including the first option portion, together with themain video, to video display apparatus 102B via a video signaltransmitting means such as an HDMI cable.

FIG. 16 is a flowchart illustrating the operations of video displayapparatus 102B according to the first example of Embodiment 3. Theoperations of video display apparatus 102B according to the firstexample of Embodiment 3 are different from those of video displayapparatus 102 according to Embodiment 1 in that steps S51 to S53 areperformed instead of step S42. Accordingly, only steps S51 to S53 willbe described, and a description of other steps will be omitted.

In video display apparatus 102B, after step S41, metadata acquirer 132acquires the main video dynamic metadata including the first optionportion (S51).

Next, generator 136 generates a second option portion from the firstoption portion of the main video dynamic metadata (S52).

Then, generator 136 outputs main video dynamic data including the secondoption portion to tone mapping processor 133 (S53).

After that, steps S43 to S45 of video display apparatus 102 according toEmbodiment 1 are performed. Video display apparatus 102B repeats theprocessing operations in steps S41, S51 to S53, and S43 to S45 until thereception of the video is completed or an operation to turn off thedisplay is performed. For example, the processing operations arerepeatedly performed for each frame or every plurality of frames.

[4-3. Configuration of Video Processing System of Second Example]

FIG. 17 is a block diagram showing a configuration of video processingsystem 100C according to a second example of Embodiment 3.

Video processing system 100C according to the second example of thepresent embodiment is different from video display apparatus 102B ofvideo processing system 100C according to the first embodiment in thatgenerator 136C of video display apparatus 102C has a different function.Other structural elements of video display apparatus 102C are the sameas those of video display apparatus 102B according to the first example,and thus a detailed description thereof will be omitted.

The format (first option) supported by the main video dynamic metadataacquired by metadata acquirer 132 and the display format (second option)are different, and thus generator 136C generates a second option portionof the dynamic metadata from the main output from video receiver 131.Then, generator 136C replaces the first option portion of the main videodynamic metadata with the generated second option portion. In this way,generator 136C extracts the dynamic metadata of the main video byanalyzing the main video, and converts the luminance dynamic rangeformat of the extracted dynamic metadata to the display format.

[4-4. Operations of Video Processing System of Second Example]

FIG. 18 is a flowchart illustrating the operations of video displayapparatus 102C according to a second example of Embodiment 3. Theoperations of video display apparatus 102C according to the secondexample of Embodiment 3 are different from those of video displayapparatus 102B according to the first example in that step S52C isperformed instead of step S52. Accordingly, only step S52C will bedescribed, and a description of other steps will be omitted.

In video display apparatus 102C, after step S51, generator 136C analyzesthe luminance characteristics of the main video output from videoreceiver 131, and generates dynamic metadata corresponding to the secondoption (or in other words, a second option portion) from the result ofthe analysis (S52C).

After that, video display apparatus 102C performs the same processingoperations as those of step S53 and the subsequent steps shown in FIG.16.

5. Embodiment 4

Embodiment 4 will be described. In Embodiment 4, in addition toEmbodiment 1 or 2, the video reproduction apparatus performs inclusionof graphics luminance information at the time of generating the secondoption portion of the dynamic metadata. That is, the video reproductionapparatus adds, to the second option portion, graphics luminanceinformation of the graphics to be overlaid on the main video. The videodisplay apparatus acquires the dynamic metadata including the secondoption portion, and performs, on a section in which the luminance of themain video corresponding to the second option is greater than or equalto the graphics luminance, a first tone mapping process of dynamicallychanging conversion characteristics according to the second optionportion of that section by using the acquired dynamic metadata, andperforms a second tone mapping process that uses constant conversioncharacteristics on a section in which the luminance of the main videocorresponding to the second option is less (darker) than the graphicsluminance.

5-1. Configuration of Video Processing System

FIG. 19 is a block diagram showing a configuration of video processingsystem 100D according to Embodiment 4. Video reproduction apparatus 101Daccording to the present embodiment is different from video reproductionapparatus 101 according to Embodiment 1 in that video reproductionapparatus 101D further includes extractor 122. Other structural elementsof video reproduction apparatus 101D are the same as those of videoreproduction apparatus 101 according to Embodiment 1, and thus adetailed description thereof will be omitted.

Extractor 122 extracts graphics luminance characteristics.

Also, video display apparatus 102D according to the present embodimentis different from video display apparatus 102 according to Embodiment 1in that tone mapping processor 133D has a different function. Otherstructural elements of video display apparatus 102D are the same asthose of video display apparatus 102 according to Embodiment 1, and thusa detailed description thereof will be omitted.

FIG. 20 is a block diagram showing a configuration of tone mappingprocessor 133D.

Tone mapping processor 133D includes coefficient calculator 141,coefficient storage 142, tone mapper 143, coefficient composer 144, andswitch SW2.

The video signal from video receiver 131 is transmitted to tone mapper143. The main video dynamic metadata from metadata acquirer 132 istransmitted to coefficient calculator 141.

Coefficient calculator 141 calculates a tone mapping coefficient used inthe tone mapping process performed by tone mapper 143 according to videodisplay capabilities such as the luminance of video display apparatus102D. Coefficient storage 142 stores the tone mapping coefficientcalculated by coefficient calculator 141. As used herein, the tonemapping coefficient refers to the coefficient included in a functionthat indicates conversion characteristics used in the tone mappingprocess. That is, the conversion characteristics are determined based onthe tone mapping coefficient.

Switch SW2 selects one from a tone mapping coefficient (A) calculated bycoefficient calculator 141 and a tone mapping coefficient (B) stored incoefficient storage 142, and inputs the selected tone mappingcoefficient to coefficient storage 142. That is, switch SW2 switchesbetween (A) updating the tone mapping coefficient stored in coefficientstorage 142 with the tone mapping coefficient newly calculated bycoefficient calculator 141 and (B) continuously storing the currentlystored tone mapping coefficient.

Coefficient composer 144 performs a dynamic tone mapping process byusing the tone mapping coefficient calculated by coefficient calculator141 when the graphics luminance information indicates “0” or a “valueindicating that there are no graphics”. On the other hand, when thegraphics luminance information indicates a value other than “0” or a“value indicating that there are graphics”, or in other words, when thegraphics luminance information indicates that graphics are overlaid,coefficient composer 144 compares the graphics luminance indicated bythe graphics luminance information and the luminance indicated by thesecond option portion of the dynamic metadata. Then, when the luminanceof the main video corresponding to the second option is greater than orequal to the graphics luminance, coefficient composer 144 performs afirst tone mapping process of dynamically changing the conversioncharacteristics according to the second option portion. When theluminance of the main video corresponding to the second option is less(darker) than the graphics luminance, coefficient composer 144 performsany one of the following processing operations of: (1) fixing tonemapping; (2) not performing a tone mapping process; (3) suppressingvariation of tone mapping; and (4) making the influence of tone mappingimperceptible to human. As used herein, the graphics luminance refers toa luminance higher than, for example, the maximum luminance value usedin graphics. With this configuration, the variation of tone mapping inthe luminance range used in graphics is suppressed. Also, in theprocessing described above, in order to maintain continuity between theconversion characteristics conversion characteristics greater than orequal to the border luminance level and the conversion characteristicsless than the border luminance level, coefficient composer 144 maycorrect the conversion characteristics in these border regions such thatthe conversion characteristics vary smoothly.

With this configuration, a portion on which graphics are overlaid can bedisplayed stably.

Also, the configuration described here is merely an example, and thustone mapping processor 133D may be configured to, when the graphicsluminance information indicates that graphics are overlaid, fix the tonemapping coefficient at a specific luminance or less, or not perform atone mapping process.

That is, with respect to a first section of the video in which thesecond option portion of dynamic metadata as first dynamic luminancecharacteristics has a luminance greater than or equal to the graphicsluminance, tone mapping processor 133D performs a first tone mappingprocess of dynamically changing the luminance of the main video in thefirst section based on the conversion characteristics according to thefirst dynamic luminance characteristics in the first section. Also, withrespect to a second section of the video in which the second optionportion of dynamic metadata has a luminance less than the graphicsluminance characteristics, tone mapping processor 133D performs a secondtone mapping process of changing the luminance of the main video in thesecond section based on constant conversion characteristics irrespectiveof the graphics luminance in the second section.

FIG. 21 is a diagram showing a configuration example of dynamic metadataaccording to Embodiment 4. In FIG. 21, illustration of the elements thatare not relevant to the present disclosure is omitted.

The configuration example of dynamic metadata shown in FIG. 21 isdifferent from that shown in FIGS. 9A, 9B, and 12 in that graphicsluminance information is added. The value of the graphics luminanceinformation indicates the effective maximum luminance of graphics (or inother words, subtitles or a menu) overlaid on the main video. When thegraphics luminance information indicates “0” or a “value indicating thatthere are no graphics”, video display apparatus 102D performs dynamictone mapping according to the dynamic metadata. On the other hand, whenthe graphics luminance information indicates a value other than “0” or a“value indicating that there are graphics”, video display apparatus 102Dperforms dynamic tone mapping on a section of the main video that has aluminance greater than or equal to the luminance of the graphicsluminance information, and fixes tone mapping on a section of the mainvideo that has a luminance less than the graphics luminance.

The graphics luminance information may be a portion of the luminancevalue distribution of the tone mapping information of the second option.As the graphics luminance information, for example, a luminance valuethat is defined as the knee point may be used. In this case, a graphicsprocess and a normal dynamic tone mapping process can be made common byvideo display apparatus 102D. That is, at a luminance less than or equalto the luminance designated by the knee point, not performing tonemapping is set as an expected value, and thus video display apparatus102D does not perform tone mapping at a luminance less than or equal tothe graphics luminance. Accordingly, even when graphics are overlaid,video display apparatus 102D can display a portion on which the graphicsare overlaid at a stable luminance.

5-2. Advantageous Effects

FIG. 22A is a diagram showing a variation in the luminance of subtitlesin conventional dynamic tone mapping in the case where graphics aresubtitles. In the case of the subtitles luminance level being 200 nitsor less, when the tone mapping varies with time, as can be seen fromFIG. 22A, the luminance at a level from 0 to near 200 nits also varies,and the subtitles luminance that essentially needs to be constantvaries.

In contrast, by setting a predetermined luminance to a fixed value andperforming tone mapping on a luminance that exceeds the predeterminedluminance, the occurrence of variation in tone mapping with time can beprevented with respect to a luminance less than or equal to thepredetermined border luminance. Accordingly, as can be seen from FIG.22B, there is no variation with time below a level of 200 nits, which isthe subtitles luminance, and thus the subtitles are displayed at astable luminance level. Here, the predetermined luminance is, forexample, a fixed value that is higher than the luminance level ofordinary subtitles, and the knee point of the conversion characteristicsis also fixed.

However, when the predetermined luminance level is fixed, a problemarises in that the range of variation of dynamic tone mapping islimited, and advantageous effects of dynamic tone mapping on the mainvideo are reduced. The problem becomes prominent particularly when themaximum luminance (DPL) of video display apparatus 102 is low. It is ofcourse possible to enhance the advantageous effects of dynamic tonemapping by devising the dynamic tone mapping method such as setting theluminance of graphics data to a predetermined value or less in videodisplay apparatus 102. However, in this case, there is a problem inthat, when graphics data having a luminance higher than the setluminance is displayed, the display of the graphics data is susceptibleto the influence of dynamic tone mapping.

To address this, in order to change the predetermined luminance based onthe subtitles luminance information, as shown in FIG. 23, dynamic tonemapping having an even higher degree of freedom can be applied to themain video. FIG. 23 shows a case where the actual subtitles luminance is100 nits. As shown in FIG. 23, in this case, dynamic tone mapping havingan even higher degree of freedom can be implemented as compared with thecase where processing is performed by fixing the border luminance to 200nits as shown in FIG. 22B. Such an advantageous effect increases as themaximum luminance of video display apparatus 102D to which the videoreproduction apparatus is connected is lower.

6. Embodiment 5

Embodiment 5 will be described. In Embodiment 5, a case will beconsidered in which a video reproduction apparatus supports a pluralityof HDR formats in which dynamic tone mapping can be performed. In thecase where the main video supports a first HDR format that is one of aplurality of HDR formats, and a video display apparatus connected to thevideo reproduction apparatus supports a second HDR format that isanother one of the plurality of HDR formats, at the time of reproducingthe main video, the video reproduction apparatus dynamically generates,from the main video that is being reproduced, dynamic metadata that isneeded in the second HDR format supported by the video displayapparatus, and transmits the generated dynamic metadata to the videodisplay apparatus. As a result, the video display apparatus acquires themain video and the dynamic metadata corresponding to the second HDRformat, and displays the acquired main video in the second HDR format byusing the acquired dynamic metadata.

[6-1. Configuration of Video Processing System]

FIG. 24 is a block diagram showing a configuration of video processingsystem 100E according to Embodiment 5. Video reproduction apparatus 101Eaccording to the present embodiment is different from video reproductionapparatus 101A according to Embodiment 2 in that generator 118E has adifferent function. Other structural elements of video reproductionapparatus 101E are the same as those of video reproduction apparatus101A according to Embodiment 2, and thus a detailed description thereofwill be omitted. Also, video display apparatus 102 has the sameconfiguration as that of video display apparatus 102 according toEmbodiments 1 and 2, and thus a detailed description thereof will beomitted.

First, the present embodiment will be described assuming that metadataacquirer 116 acquires main video dynamic metadata corresponding to thefirst HDR format. It is also assumed that format acquirer 117 acquiresthe display format indicated by the second HDR format because the HDRformat supported by the display format of video display apparatus 102 issecond HDR format.

The format (first HDR format) supported by the main video dynamicmetadata acquired by metadata acquirer 116 and the display format(second HDR format) acquired by format acquirer 117 are different, andthus generator 118E generates dynamic metadata in the second HDR formatfrom the main video output from main video decoder 113. Then, generator118E replaces the dynamic metadata in the first HDR format with thegenerated main video dynamic metadata in the second HDR format, or addsthe generated dynamic metadata in the second HDR format to the mainvideo dynamic metadata. In this way, generator 118E extracts the dynamicmetadata of the main video corresponding to the display format byanalyzing the main video.

7. Variation

The details of Blu-ray and Ultra HD Blu-ray are disclosed in, forexample, Non-Patent Literature (NPL) 1.

The HDR video acquired by acquirer 111 may be a video on, for example, aBlu-ray disc, a DVD, a moving image delivery site on the Internet, abroadcast, or a HDD (Hard Disk Drive).

The video reproduction apparatus described above may be an apparatusthat decodes a compressed video signal transmitted from a recordingmedium, a broadcast, or the Internet, and transmits the decoded videosignal to a video display apparatus. Examples of the video reproductionapparatus include a disc player, a disc recorder, a set top box, atelevision set, a personal computer, and a smartphone. Also, videodisplay apparatus 102 may have some or all of the functions of the videoreproduction apparatus. For example, among the processors included inthe video reproduction apparatus, video display apparatus 102 mayinclude the processors other than acquirer 111. Also, video receiver131, metadata acquirer 132, and tone mapping processor 133 or 133Dincluded in video display apparatus 102 or 102D may be incorporated inthe video reproduction apparatus. Also, among the processors included intone mapping processor 133D, the video reproduction apparatus mayinclude the processors other than tone mapper 143.

The video signal transmitting means that transmits the video signal fromthe video reproduction apparatus to the video display apparatus may be ameans that transmits the video signal in an uncompressed state such asHDMI, DVI, or DP, or may be a means that transmits the video signal in acompressed form such as transmission via a network.

The maximum luminance information or the tone mapping information of thevideo display apparatus can be set in the video reproduction apparatusby a user inputting the information into the video reproductionapparatus via a remote controller or the like, or via an operatingapparatus included in the video reproduction apparatus. Alternatively,the user may acquire these information via the Internet or any othermeans, store the acquired information in a portable storage medium, andtransmit the information to the video reproduction apparatus via theportable storage medium. Alternatively, the video reproduction apparatusmay be connected directly to the Internet such that the videoreproduction apparatus can acquire these information from a database ona server. Furthermore, the video reproduction apparatus may display atest pattern on the video display apparatus such that these informationcan be acquired or stored, with the user confirming the characteristicsof the video display apparatus by using the displayed test pattern.

The video reproduction apparatus may generate graphics luminanceinformation (including subtitles luminance information and menuluminance information) by detecting the luminance of graphics (subtitlesor a menu) from the data of the graphics, or may acquire the luminanceof graphics created in advance during production of the video data. Forexample, the graphics luminance may be recorded in a disc, or may betransmitted as metadata via broadcasting or the Internet. The videoreproduction apparatus reads the graphics luminance, and transmits theread graphics luminance to the video display apparatus as a portion ofthe dynamic metadata. Alternatively, the luminance information ofgraphics (subtitles or a menu) may be recorded in a database on a serverthat is connected to the Internet as information regarding the contentto be reproduced such that the video reproduction apparatus can acquirethe graphics luminance information from the database, and transmit theacquired graphics luminance information to the video display apparatus.

The metadata of the first option and the metadata of the second optionmay be provided in different descriptions that are different from thebit number and the number of items of the configuration examples, suchas a coordinate system of a unit system of the values of the firstoption being different from a coordinate system of a unit system of thevalues of the second option.

In Embodiments 1 to 4, a case has been described in which the firstoption and the second option of the HDR format are different. However,the expression the HDR format being different also encompasses that thefirst option and the second option are different. That is, the firstoption of the HDR format may be defined as a first HDR format, and thesecond option of the HDR format may be defined as a second HDR format.Also, Mandatory HDR may be an HDR format that is different from thefirst option of the HDR format and the second option of the HDR format.

Up to here, the video processing systems according to the embodiments ofthe present disclosure have been described, but the present disclosureis not limited to the embodiments.

Also, the processors included in the video processing systems accordingto the embodiments described above are typically implemented as LSIs,which are integrated circuits. They may be individual single chips, or apart or all of them may be configured in a single chip.

Also, implementation of an integrated circuit is not limited to an LSI,and may be implemented by a dedicated circuit or a general-purposeprocessor. It is also possible to use an FPGA (Field Programmable GateArray) that can be programmed after LSI production or a reconfigurableprocessor that enables reconfiguration of the connection and setting ofcircuit cells in the LSI.

Also, in each of the embodiments described above, the structuralelements may be configured using dedicated hardware, or may beimplemented by executing a software program suitable for the structuralelements. The structural elements may be implemented by a programexecutor such as a CPU or a processor reading and executing a softwareprogram recorded in a recording medium such as a hard disk or asemiconductor memory.

Also, the present disclosure may be implemented as a method executed bythe video processing system.

Also, the functional blocks shown in the block diagrams are merelyexamples. Accordingly, it is possible to implement a plurality offunctional blocks as a single functional block, or divide a singlefunctional block into a plurality of blocks. Alternatively, somefunctions may be transferred to other functional blocks. Also, thefunctions of a plurality of functional blocks that have similarfunctions may be processed by a single piece of hardware or software inparallel or by time division.

Also, the order in which the steps of each flowchart are performed ismerely an example provided to specifically describe the presentdisclosure. Accordingly, the order is not limited to that describedabove. Also, one or more of the steps described above may be performedsimultaneously with (in parallel to) other steps.

A video processing system according to one or more aspects has beendescribed by way of embodiments above, but the present disclosure is notlimited to the embodiments given above. Embodiments obtained by makingvarious modifications that can be conceived by a person having ordinaryskill in the art to the above embodiments as well as embodimentsimplemented by any combination of the structural elements of differentembodiments without departing from the gist of the present disclosuremay also be encompassed within the scope of one or more aspects.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to a video processing system, avideo reproduction apparatus, or a video display apparatus.

What is claimed is:
 1. A video processing system, comprising: a mainprocessor; and a memory storing a program, wherein the program, whenexecuted by the processor, causes the main processor to perform:acquiring video data including a main video and a first luminancedynamic range format; acquiring a display format that indicates a secondluminance dynamic range format displayable by a display apparatus;determining whether the first luminance dynamic range format is same asor different from the second luminance dynamic range format; generatingfirst characteristics information that indicates first dynamic luminancecharacteristics that correspond to the display format by using the videodata when the first luminance dynamic range format is different from thesecond luminance dynamic range format, the first dynamic luminancecharacteristics being dynamic luminance characteristics indicating atime-dependent change in luminance characteristics of the main video,the first characteristics information being dynamic meta data used in atone mapping process sequentially performed in the display apparatus;and outputting the first characteristics information generated in thegenerating, wherein: the video data further includes secondcharacteristics information that indicates the dynamic luminancecharacteristics of the main video, in the generating, the firstcharacteristics information is generated by converting a secondluminance dynamic range format of second dynamic luminancecharacteristics indicated by the second characteristics information tothe display format, a format of the first characteristics informationand a format of the second characteristics information are differentfrom each other, and the first dynamic luminance characteristicsindicated in the first characteristics information and the seconddynamic luminance characteristics indicated in the secondcharacteristics information are equivalent.
 2. The video processingsystem according to claim 1, wherein the generating the firstcharacteristic information comprises generating the firstcharacteristics information by analyzing the main video of the videodata to extract the second dynamic luminance characteristics indicatingthe dynamic luminance characteristics of the main video, and convertingthe third luminance dynamic range format of the second dynamic luminancecharacteristics extracted to the display format.
 3. The video processingsystem according to claim 1, further comprising: a tone mappingprocessor that performs a tone mapping process of converting a luminanceof the main video based on conversion characteristics according to thefirst dynamic luminance characteristics indicated by the firstcharacteristics information output in the outputting; and a display thatdisplays the main video that has undergone the tone mapping process. 4.The video processing system according to claim 1, further comprising: acomposer that generates a composite video by overlaying graphics on themain video; and an extractor that extracts luminance characteristics ofthe graphics, wherein the outputting further comprises outputting thecomposite video and third characteristics information that indicates theluminance characteristics of the graphics.
 5. The video processingsystem according to claim 4, further comprising: a tone mappingprocessor that performs a tone mapping process of converting a luminanceof the main video based on conversion characteristics according to thefirst dynamic luminance characteristics indicated by the firstcharacteristics information output in the outputting; and a display thatdisplays the main video that has undergone the tone mapping process,wherein, when the composite video is generated by the composer, the tonemapping processor performs: a first tone mapping process on a firstsection of the main video in which the first dynamic luminancecharacteristics indicated by the first characteristics information aregreater than or equal to the luminance characteristics of the graphicsindicated by the third characteristics information, the first tonemapping process being processing of dynamically changing the luminanceof the main video in the first section based on the conversioncharacteristics according to the first dynamic luminance characteristicsin the first section; and a second tone mapping process on a secondsection of the main video in which the first dynamic luminancecharacteristics are less than the luminance characteristics of thegraphics, the second tone mapping process being processing of changingthe luminance of the main video in the second section based on constantconversion characteristics irrespective of the first dynamic luminancecharacteristics in the second section.
 6. A video processing method in avideo processing system, the video processing method comprising:acquiring video data including a main video and a first luminancedynamic range format; acquiring a display format that indicates a secondluminance dynamic range format displayable by a display apparatus;determining whether the first luminance dynamic range format is same asor different from the second luminance dynamic range format; and afterit is determined that the first luminance dynamic range format isdifferent from the second luminance dynamic range format, generatingfirst characteristics information that indicates first dynamic luminancecharacteristics that correspond to the display format by using the videodata, the first dynamic luminance characteristics being dynamicluminance characteristics indicating a time-dependent change inluminance characteristics of the main video, the first characteristicsinformation being dynamic meta data used in a tone mapping processsequentially performed in the display apparatus, and outputting thefirst characteristics information generated in the generating of thefirst characteristics information, wherein: the video data furtherincludes second characteristics information that indicates the dynamicluminance characteristics of the main video, in the generating, thefirst characteristics information is generated by converting a secondluminance dynamic range format of second dynamic luminancecharacteristics indicated by the second characteristics information tothe display format, a format of the first characteristics informationand a format of the second characteristics information are differentfrom each other, and the first dynamic luminance characteristicsindicated in the first characteristics information and the seconddynamic luminance characteristics indicated in the secondcharacteristics information are equivalent.
 7. A video processingsystem, comprising: a main processor and a memory storing a program,wherein the program, when executed by the processor, causes the mainprocessor to perform: acquiring video data including a main video;acquiring a display format that indicates a luminance dynamic rangeformat displayable by a display apparatus; generating firstcharacteristics information that indicates first dynamic luminancecharacteristics that correspond to the display format by using the videodata when a luminance dynamic range format of the main video indicatedby the video data is different from the display format, the firstdynamic luminance characteristics being dynamic luminancecharacteristics indicating a time-dependent change in luminancecharacteristics of the main video, the first characteristics informationbeing dynamic meta data used in a tone mapping process sequentiallyperformed in the display apparatus; outputting the first characteristicsinformation generated in the generating; generating a composite video byoverlaying graphics on the main video; extracting luminancecharacteristics of the graphics; a tone mapping processor that performsa tone mapping process of converting a luminance of the main video basedon conversion characteristics according to the first dynamic luminancecharacteristics indicated by the first characteristics informationoutput in the outputting; and a display that displays the main videothat has undergone the tone mapping process, wherein the outputtingfurther comprises outputting the composite video and thirdcharacteristics information that indicates the luminance characteristicsof the graphics, and wherein, when the composite video is generated, thetone mapping processor performs: a first tone mapping process on a firstsection of the main video in which the first dynamic luminancecharacteristics indicated by the first characteristics information aregreater than or equal to the luminance characteristics of the graphicsindicated by the third characteristics information, the first tonemapping process being processing of dynamically changing the luminanceof the main video in the first section based on the conversioncharacteristics according to the first dynamic luminance characteristicsin the first section; and a second tone mapping process on a secondsection of the main video in which the first dynamic luminancecharacteristics are less than the luminance characteristics of thegraphics, the second tone mapping process being processing of changingthe luminance of the main video in the second section based on constantconversion characteristics irrespective of the first dynamic luminancecharacteristics in the second section, the video data further includessecond characteristics information that indicates the dynamic luminancecharacteristics of the main video, in the generating, the firstcharacteristics information is generated by converting a secondluminance dynamic range format of second dynamic luminancecharacteristics indicated by the second characteristics information tothe display format, a format of the first characteristics informationand a format of the second characteristics information are differentfrom each other, and the first dynamic luminance characteristicsindicated in the first characteristics information and the seconddynamic luminance characteristics indicated in the secondcharacteristics information are equivalent.
 8. The video processingsystem according to claim 1, wherein: the video data includes: astandard high definition range (HDR) video, an HDR video of a firstformat which is a higher quality video than the standard HDR video, andthe first characteristics information indicates first dynamic luminancecharacteristics that correspond to the HDR video of the first format. 9.The video processing system according to claim 8, wherein the displayapparatus is configured to display an HDR video of a second format whichis a higher quality video than the standard HDR video.
 10. The videoprocessing method according to claim 6, wherein: the video dataincludes: a standard high definition range (HDR) video, an HDR video ofa first format which is a higher quality video than the standard HDRvideo, and the first characteristics information indicates first dynamicluminance characteristics that correspond to the HDR video of the firstformat.
 11. The video processing method according to claim 10, whereinthe display apparatus is configured to display an HDR video of a secondformat which is a higher quality video than the standard HDR video. 12.The video processing system according to claim 7, wherein: the videodata includes: a standard high definition range (HDR) video, an HDRvideo of a first format which is a higher quality video than thestandard HDR video, and the first characteristics information indicatesfirst dynamic luminance characteristics that correspond to the HDR videoof the first format.
 13. The video processing system according to claim12, wherein the display apparatus is configured to display an HDR videoof a second format which is a higher quality video than the standard HDRvideo.